The present invention mainly relates to a frame structure of a construction machine vehicle having a crawler travelling apparatus, and relates to a frame structure of a crawler-type construction machine vehicle capable of strengthening total rigidity and capable of setting a gravitational center position at an optimum location in accordance with a variation in vehicle kind while retaining a basic configuration.
Conventionally, a construction machine vehicle having crawler travelling apparatus is constructed such that an engine and a mechanical power transmission apparatus are mounted on a vehicle frame, and crawler driving reduction gears are interposed between the vehicle frame on which the power transmission apparatus and track frames of the left and right crawler travelling apparatus to connect and integrate the vehicle frame and the track frames. According to the vehicle with such arrangement, a connecting and attaching position of the vehicle body frame and the track frames is restrained by a position of the crawler driving reduction gears to be uniquely determined thereby.
Therefore, in to the conventional construction machine vehicle, since the positions of connecting and attaching the vehicle body frame to the track frames cannot be selected, a problem is posed that the vehicle body balance must be carefully set in order to make the gravitational center of the vehicle body be at a proper position of the track frames.
Meanwhile, in recent times, it is necessary to fabricate vehicle kinds having various conditions by request of a user. Therefore, constitution and specification of vehicle body frame and the crawler travelling apparatus are requested to change in accordance with a variation of vehicle kind such as a crawler travelling apparatus having a long ground length and a crawler traveling apparatus widening an intercrawler distance between left and right crawlers. However, there poses a problem that reforming of structure to meet the request is not easy and is in a large scale.
With regard to the problem, according to U.S. Pat. No. 5,894,908, there is proposed an integrated frame for strengthening total rigidity by completely integrating an upper vehicle frame and a lower track frames. However, according to the constitution, a crawler travelling apparatus in accordance with variation of the vehicle kind (for example, crawler travelling apparatus prolonging the ground length, crawler travelling apparatus widening intercrawler distance of left and right crawlers) cannot simply be reformed without changing the basic configuration. Further, the upper vehicle frame cannot be integrated to track frames by coupling these at a pertinently selected position while corresponding to the vehicle body gravitational center position.
Further, some studies have been disclosed, for example, with respect to a bulldozer, although in order to promote the rigidity of the frame structure of the vehicle body or achieving light-weighted formation, in, for example, Japanese Utility Model Laid-Open No. 51083/1994, and Japanese Utility Model Laid-Open No. 49284/1994, however, these constitutions only achieve rationalization by using members in a pipe-like shape for cross bars for coupling main frames and track frames and there poses a problem that in order to correspond to variation of vehicle kind, the structure must be totally reformed.
The invention has been carried out in view of the above-described problem and it is an object thereof to provide a frame structure of a crawler type construction machine vehicle which can be easily reformed in accordance with a variation of vehicle kind by simplifying a structure of integrating a track frame of a crawler travelling apparatus and an upper vehicle body frame, which can set a vehicle body gravitational position at an optimum location by enabling to install the upper vehicle body frame at an arbitrary position and capable of strengthening total rigidity by enabling to constitute an integrated structure.
In order to achieve the above-described object, according to the invention, there is provided a vehicle frame structure of a crawler type construction machine vehicle which integrates a pair of left and right track frames and vehicle body frames into a rigid structure:
wherein a pair of track frames installed in parallel with each other by providing an interval therebetween in a left and right direction, are integrally coupled by front and rear cross beams bridging the left and right track frames;
wherein a pair of left and right vehicle body frame members installed in parallel with each other and in parallel with the left and the right track frames within a width of the interval of the left and the right track frames are integrally coupled to bridge upper positions of the front and the rear cross beams; and
wherein the pair of left and right track frames and the pair of left and right vehicle body frame members are integrally coupled by the front and the rear cross beams.
According to the invention, there is provided a lattice-like coupling structure for orthogonally coupling the front and rear cross beams to the pair of left and right track frames by a required arrangement and orthogonally coupling the vehicle body frame members to the front and rear cross beams at upper positions thereof. In this way, the left and the right track frames, the front and rear cross beams and the vehicle body frame members are each constituted as skeleton frames respectively independent from each other and therefore, there is achieved a degree of freedom of design. Therefore, the change of the variation of the vehicle body, for example, reattaching a crawler travelling apparatus having a long ground length prolonging the track frames or a vehicle widening an intercrawler distance of the left and right crawler travelling apparatus by prolonging lengths in the left and right direction of the front and rear cross beams, can be carried out only by changing independent essential portion members and there is achieved an effect that the design change is facilitated. Further, by pertinently adjusting and setting position of coupling the track frames and the vehicle body frame members relative to the front and rear cross members, an optimum gravitational position of the vehicle body in accordance with a changed product can arbitrarily be selected and there is achieved an effect of providing a rational vehicle body structure. It is noted that crawler driving reduction gears use hydraulic driving reduction gears built with hydraulic motors attached to the track frames and therefore, the positional relationship between the vehicle body frame and the track frames is not restrained as in using a conventional mechanical driving reduction gears and therefore, the object can be achieved.
According to the invention, it is preferable that the pair of left and right vehicle body frame members include long vertical plate beams, notched portions are provided at two locations in a longitudinal direction of lower sides of the vertical plate beams, the respective notched portions in the shape of the reverse recess are fitted to the front and the rear cross beams and the vertical plate beams are integrally coupled to the front and the rear cross beams in an intersected shape. By constituting this way, the vehicle body frame members are brought in mesh with the front and rear cross beams at the notched portions in the shape of the reverse recess to thereby constitute the lattice like coupling and therefore, a resistance against strain in a face in the horizontal direction of the front and rear cross beams and the track frame, is promoted and the total rigidity can be ensured.
Here, it is preferable that an interval between lower ends of the pair of left and right vertical plate beams is connected by a bottom plate member and an interval between rear ends thereof is connected by a vertical wall member directed vertically covering from upper faces of the rear ends of the left and the right vertical plate beams over to rear faces of the rear side cross beam.
Further, it is preferable that portions of the pair of left and right vehicle body frame members extending between the front side cross beam and the rear side cross beam are constituted to be box beam portions. When such a constitution is adopted, the left and right track frames are coupled by the box beam portions arranged at front and rear thereof to thereby constitute the lattice-like coupling structure and therefore, rigidity in the vertical direction is promoted and the structure can sufficiently stand load from the lift cylinders for an earth-moving machine.
Further, it is preferable that attaching brackets of lift cylinders for the earth-moving implement are provided at upper faces of front portions of the box beam portions and a sectional area of the box beam portion is gradually increased from a position of the attaching bracket of the lift cylinder for the earth-moving implement to the vertical wall member. By constituting in this way, operating force applied to the attaching brackets of the lift cylinders for the earth-moving implement can be distributed toward the rear side cross beam and light-weighted formation can be achieved by simplifying structure of portion other than necessary.
Further, it is preferable that the vertical wall member in right angle is attached with a frame base constituting an upper face thereof by a platform and constituting a lower face thereof by a support portion of the attachment. By constituting in this way, operating reaction force from the attachment is distributed to the vehicle body frames and to the rear cross beam and accordingly, operation of absorbing vibration is high and there is achieved an effect of capable of alleviating propagation of vibration to the vehicle body frame.
According to the invention, it is preferable that the left and the right track frames each includes, in a longitudinal direction, a bifurcated idler support frame portion at a front portion thereof, a frame portion having a section in a box-like shape with a roller attaching face at a middle portion thereof and a frame portion for attaching crawler driving reduction gears built with hydraulic motors offset to an inner side of the vehicle body from the middle portion at a rear portion thereof;
wherein the frame portions for attaching the crawler driving reduction gears built with the hydraulic motors are matched to rear face sides of two end portions of the rear cross beam and inner side faces of the frame portions having the section in the box-like shape are matched to the front and the rear cross beams and two end faces of the rear cross beam to thereby integrally couple with each other. By constituting in this way, the track frames are constituted by the integrated structure and therefore, positions of attaching the driving reduction gears built with the hydraulic motors related to drive and guide of the crawlers and positions of attaching roller attaching portions can be machined with excellent dimensional accuracy and even when the portions are fixedly attached integrally to the front and rear cross beams, there is no change in accuracies of the attaching positions and therefore, the crawlers are rotated smoothly. Further, the offset attaching frames of the hydraulic driving reduction gears are fixedly attached to the rear face of the rear cross beam and therefore, there is achieved an effect of sufficiently maintaining rigidity in view of strength.